Manual liquid dispensers of various sort have been widely implemented in a variety of applications. One type of liquid dispenser is a manually operated pump that is arranged to prepare a foam from a liquid in a container, and to dispense such foam under manual operation of the pump. In typical arrangements, the dispenser is in the form of a reciprocating pump that is manually operated by force applied against a restorative spring force of an expansion spring within a dispenser device, with the application and removal of the external force being sufficient to generate pressure changes in respective air and liquid chambers in the dispenser to alternately cause foaming/dispensing and intake of air and liquid for liquid foaming in the next pumping cycle.
A common type of foam dispenser includes those used in daily cosmetic and medicinal applications. Liquid force under pressure into an air-liquid mixing chamber generates a foamable mixture that, when forced through an obstruction, develops a relatively dense dispensable foam. Typically, liquid foaming dispensers of this type comprise a pump housing which contains an air pump chamber and a liquid pump chamber, and a piston that is manually reciprocated in the pump housing. The air piston and the liquid piston are mounted for reciprocating movement in the respective air and liquid chambers, such that movement of the pump against a spring force causes the air piston to move in the air chamber to thereby exert a compression force on the air in the chamber, and likewise the liquid piston in the liquid chamber to exert a compression force on the liquid in the liquid chamber. Valves control the flow of air and liquid from the respective air chamber and liquid chamber into an air-liquid mixing chamber where the air and liquid are mixed and driven through a foaming obstruction to generate the dispensable foam.
Release of the external downward force to the pump permits the spring to expand under its restorative force, and to thereby return the pumping mechanism to its extended position. This movement of the pump mechanism causes the air piston and the liquid piston to move in their respective air chamber and liquid chamber in a manner which expands the interior volumes of the two chambers. The negative pressures created by such movement draws air into the air chamber and liquid into the liquid chamber. Valve assemblies are typically employed in controlling the flow of air and liquid into the respective air chamber and liquid chamber as their interior volumes are increased by the movement of the pump mechanism.
While many pumping mechanisms and valve assemblies have been developed in the past to provide the functionality described above, efficiency and manufacturing can be a substantial driver in the marketability of such manual foaming dispensers. Therefore, improvements in the design of the foaming dispenser which even slightly reduces the manufacturing costs can result in significant benefit to the manufacture and sale of liquid foaming dispensers. Additionally, improvements can be made to the mechanism, including the valving arrangements, in order to more efficiently produce a consistent foam, and to limit “bleed” of air and/or liquid out from a designated operational pathway.
It is therefore an object of the invention to provide a liquid foaming dispenser which improves manufacturability.
It is another object of the present invention to provide a liquid foaming dispenser which improves operational effectiveness.